18 Sep
2010
18 Sep
'10
9:51 a.m.
Alex Tinsley wrote:
First off any noise that you hear through your USB
Audio interface is
because the grounding in the audio device is using the grounding on the
laptop which is most commonly data ground wired to earth ground. So you
hear all computer noise through the audio output. One way to alleviate
this is to lift the ground on the laptop (unplug the power adapter from
the laptop or get a ground lift adapter). Noise goes away. A lot of
devices suffer from this, 1394 has same issue.
I only get noise on my USB soundcard when I plug it into my external
hub. I get no noise with it plugged directly into the laptop. I guess
the laptop ground is OK and the external hub's ground is junk.
The hub has other devices plugged into it, I don't recall if I tried
using it with only the soundcard. Wouldn't be surprised if some of the
other USB devices on the hub (scanner, printer, MIDI interface,
PS/2<>USB adapter for keyboard & mouse, flash card reader) are sources
of noise by themselves.
Thanks for the extensive info!
--
David
gnome(a)hawaii.rr.com
authenticity, honesty, community